Looking for recommendations regarding the size of the header primary tube.

Intended use is (M-body in the sig, 3600 lbs race weight): weekend driver, not a drag racer, a typical street/light-strip car. W2 based 408 stroker, forged crank, H-beam rods, 10.5:1 CR, hydraulic roller cam, 6500 max RPM, 4k converter, 4.10 rear end ratio.

I am moving to the TTI headers, specifically looking at the 340W2 (1-5/8" primary) or 340W2-17835 (1-7/8" primary) setups.

Previously I have only ran 1-5/8" tubes, always on a stock displacement motor (360"), these worked well on the car. The remainder of the exhaust are dual 3" pipes with X-pipe, all feeding into Hooker MaxFlow mufflers.

Given the move to a stroker (408) and the cost of these headers in particular, I am wondering whether I should be looking at the 1-7/8" tubes in order to get some "room to grow"?

While I always aim for max-performance effort within a particular combo, this is not a motor that will spend a lot of time in the upper RPM, it simply is not a drag race vehicle.

My original thinking was to stay with the 1-5/8 tubes, but given the extra cubic inches that the stroker brings, the fact that at WOT I push the converter to the 4k stall and with the 4.10 gears it'll buzz real quick I am now wondering what the best option is. What do you recommend?
1980 Dodge Diplomat Coupe, 360-4bbl, 727, 3.91 SG motivated sleeper! 1981 Dodge Diplomat Coupe, /6 38K mi. survivor car, awaiting restoration.